Question

4. A car is uniformly moving at a speed of 20m/s. If it has to be uniformly brought to rest in 10 seconds, at how much distance from the final destination must be apply the brakes to the car.
Calculate the uniform retardation.

Answer 1

Answer:

Answer

Given,

Speed=20m/s,d=50m,retardation=5m/s

2

Let the ppossible reaction time be t

s

So the car moves 20tm And applied breaks with retardation 5m/s

2

So, the total distance under retardation is ≤50m

Thus the distance under the application of retardation =

2×5

20

2

−0

2

=s

′

⇒s

′

=40m

Therefore, 20t

s

+40≤=50⇒20t

s

≤50−40⇒20t

s

=10⇒t

s

≤

2

1

≤0.5s